|
jcjeant, the analysis by the Russian Interstate Aviation Group and BEA concluded there was about a 55 percent probability that the impact would be within 6 NM from the "start of the emergency", and nearly 70 percent probability it would be within 8 NM. It seems the Metron analysis used the LNP as the "start of the emergency" for purposes of its calculations. But the LNP is rather late in the sequence,
Perhaps a reason the BEA is not releasing the exact coordinates is that it may be closer to the LNP then many of us assume, and if so, both Brazil and France would have overflown the impact point on both June 1 and June 3. (France clearly overflew it on June 1 (wherever it turns out to be) given the search graphic in the Metron analysis for June 1.) If visual conditions for the search on June 1 were poor, one would think that search would be repeated when conditions were improved. That seems not to be the case. I am certain that an impact quite close to the LNP would raise all manner of questions about the adequacy of the initial searches, and that would be a subject that the BEA and the French and Brazilian military would rather not be distracted by at this point. There was also a ship, the Douce France, that searched in the area of the LNP on June 1, but its track has not been publicly released. |
BJ-ENG
I think it more likely that if at impact, the VS separated and was thrown back. The Pressure vessel terminates at the Aft Bulkhead, and the a/c essentially flies (and crashes) in close formation with the Tail. If tail first, the dynamics of Hydraulic action would emanate differently than at the Fuselage, not to mention the likelihood that the Tail may have completely separated from the body at impact. If there was a separation at impact, the angle of attachment would grow progressively more acute, suffering the remaining structure to progessively separate from its closest neighbors still connected to the hull. The fuselage, having acted in essence as a giant airbag, would accelerate the loss of velocity of the fuselage as the tail continued. If the body 'rebounded' (that certainly would need explanation), the tail may have been 'rejected' (rather emphatically) by the Fuse and the VS pulled itself loose from the forward lug/bracket and flew backwards to escape corruption by a presence in the chaotic debris of the main impact area. This would basically (sic) explain the damage to the VS' LE via contact with the dorsal area of the fuselage at initial deceleration, (the tail having 'folded over' this area) and the corrupted corner of the Rudder as the Fin/Rudder rolled over the tail cone in aft fashion with the violent pull on the empennage by the fuselage remaining essentially near the surface after initial contact. jcjeant What is seductive to me is some verbiage expressed by the BEA that may lead to false assumptions. It seems completely apparent that 447 departed controlled flight. The late portion of the fall by BEA's description is of a free fall with some horizontal component, and a slight lateral rotation of the airframe, with the a/c essentially intact. There was no aerodynamic flight. 447's trajectory was down, and her hull had no heading, by their own explanation. Intact, this aircraft's nose would have a heading only after all its rotation had ceased. It's nose was unwinding the compass' rose in a left rotation, laterally. There was no heading. No Flight, No Heading. No "En Ligne de Vol". I wager 98 per cent of the reading public think the aircraft was in controlled flight on her way to Paris when by misfortune she hit the water. Words have meaning. |
One scenario
Instead of not having enough altitude for a square loop, imagine a transition from a wings-level high-speed pullout during a spiral dive recovery to a relatively low-forward speed, nose-up, high-sink rate impact with the water:
Aviation Video: FA-18 MCAS El Toro Crash | Patrick's Aviation A loss of control eventually resulting in a spiral dive also keeps them in the vicinity of the LKP. |
Originally posted by bearfoil ... There was no aerodynamic flight. 447's trajectory was down, and her hull had no heading, by their own explanation. Intact, this aircraft's nose would have a heading only after all its rotation had ceased. It's nose was unwinding the compass' rose in a left rotation, laterally. That resulted in the tail swinging to port (left) on impact and following the culmination of the forces acting on its clevis joints in all planes and vectors, not forgetting the reciprocal buoyancy forces, the Vertical Stabilizer finished up in the water on its port-side with its rudder hard to starboard. At the time of the impact, the wind was from the north at 25~30 knots, and the rudder aspect was such that the V/S was quite capable of "sailing" away from the scene. |
Hi,
At the time of the impact, the wind was from the north at 25~30 knots, and the rudder aspect was such that the V/S was quite capable of "sailing" away from the scene. So I stay with ONE of my wonder: (provided the VS separated on impact) Why this VS was not discovered during the first aerial researches in the vicinity of the LKP.... ? This VS is not the size of a little plastic bag or a lifevest and have not the abilities of a submarine (dive and surface at his will) |
Originally posted by jcjeant ... Why this VS was not discovered during the first aerial researches in the vicinity of the LKP.... ? |
mm43
bonjour. The VS was semi submerged when spotted, its colors probably difficult to discern. The structure gave me the impression of never being 'proud' of the surface, and I assumed it acted as its own sea anchor from loss to discovery. BEA stated that the Rudder was flapping, and had no resistance to pressure in its axis of sweep. I do not think it "sailed" at all. I can not remember its position when found, but was it not WNW of LKP a fair bit? Does this not conflict with your winds from 000 at ~25-30 ?? I also conclude the VS did not sink with other structure, to break free and surface on its own. It would have had to retain some air in pockets, and at 50 meters, it would have experienced permanent rib collapse, no? Permit me a display of ignorance or inattention, (both?) but the LKP at 02:10, is that actual, timed transmission stamp, or receipt by ACARS?? My feeling is twofold, and I cannot blame BEA and/or ABI/AF. No one involved who had a stake in this accident wanted to believe that this sota a/c fell out of the sky, steeply, especially having lost some bits. I think their bias to 40 nm away or further reflects some wishful thinking on their part. Understandable. |
bear,
LNP @ 2.58.8'N 30.35.4'W VS sighted June 6 @ 13h38 @ 3.61 N 30.62 W VS recovered June 7 @ 18h35 @ 3.47N 30.68W On June 1, north of the LKP, surface winds were blowing from the NNE to NE direction, with much convection. On June 2 and days following, winds became more easterly, and decreased. Convection was less as well. On June 1, the drift group's optimal interpolation of the current near the LNP is that it was from the N/NNE toward the S/SSW, South of 3N, the current quickly turns SE and then east. |
If AF447 lost its VS in flight, it would have resulted in a CG shift forward. I don't know the mass of the VS, but would it have been enough of a shift to prevent a level attitude, if not the presumed slight nose high, at impact?
|
If the VS separated when the tail was submerged, especially the closer the wreckage got to the bottom, I suspect to some degree it would glide to the surface. Depending on which area has the most buoyancy it might make a series of gliding loops, or swirl like Sycamore seed. In most pictures the rudder was also positioned to the starboard side, if firmly enough in that position it would also affect the ascent.
My guess would be that the deeper the VS separated the more likely it is to be found farther from the impact site. Even if it were to rise perfectly vertical the subsurface currents would have a longer time to act upon it. A piece of wreckage like a cabin section might tumble upon ascent, but seems less likely to glide or sail than something aerodynamic. Once upon the surface it will all depend on wind and currents, and whether there is more submerged or exposed area to be acted upon by each. Wreckage with a similar profile might stay together, but again over time one would expect those items more driven by wind or currents to separate. |
I'm obviously missing something, I would have thought that if the VS separated at any sought of real depth it would still be down there?:confused:
|
BJ-ENG...
Superb post. |
Grizz, I completely agree. BJ-ENG's post is in my view required reading. Understanding the difference between aircraft structures impacting solid ground and water is, I think, important to understanding what the photographs have shown us in terms of the "stopping" capacity of water vs level ground, (ie, Tripoli vs what we see here thus far). I think how BJ-ENG's post describes this difference has added a great deal to the thread's knowledge.
|
Khashoggi:
Originally Posted by cc45; post #1116 (p.56)
The VS weighed about 1800 kg and had an area of 53 m^2.
|
deSitter,
jcjeant - that's right - the great unknown in all of this is the behavior of composite structures under atypical stresses - there are many competing models, often mutually wildly divergent, all highly non-linear, of composite failure under stress. If you had done so you would have noticed that it was primarily the METAL support structure that broke not the composites. In contrary the composites survived the loads much better than the 'tin' (as is often the case btw.). That makes any philosophying about the strength of composites obsolete. Sorry if I sound a bit rude but it starts to get annoying having unfounded generalisation (which oviously does not apply in this case) repeated over and over again. jcjeant, .. as a consequence of the loss of VS in flight is that you get a plane that is no more controllable ... what appears to have been the case for AF447 AA587 impacted in a spiral dive, not flat btw. |
Originally Posted by bearfoil
(Post 6403323)
Permit me a display of ignorance or inattention, (both?) but the LKP at 02:10, is that actual, timed transmission stamp, or receipt by ACARS??
AF447 ACARS MESSAGES - Color Coded & Interactive Version BEA use these receipt times to report end of the flight between 2 h 14 min 26 and 2 h 15 min 14 If you want to repeat this the numbers used by the BEA in the flight path graphic time in seconds 'rounded to nearest minute', decimal location to ACARS 2 decimal place precision given in http://www.bea.aero/en/enquetes/flig...data/AF447.txt |
VS (FIN & Rudder) Sailing Performance
Quote[FONT=Verdana][SIZE=2] from SaturnV:
LNP @ 2.58.8'N 30.35.4'W VS sighted June 6 @ 13h38 @ 3.61N 30.62W VS recovered June 7 @ 18h35 @ 3.47N 30.68W [unquote] Just to point out that the quoted positions appear to be defined as follows: LNP (LKP) position is in degrees/minutes/decimals-of-minutes. However, VS positions are in degrees/decimals-of-degrees. VS (fin) posn June06/1338: N03.61/W030.62 º N03°36.6'/W030°37.2' VS (fin) posn June07/1835: N03.47/W030.68 º N03°28.2'/W030°40.8' I don't know how accurate the "sighted" position would have been, but here goes the number-crunching. (Not sure if the VS position-timings are GMT, but that doesn't affect the issue.) In roughly 29 hrs, 6 days after the accident, the VS apparently moved 9.1 nm (16.9 km) on mean TRK 203°T Taken on face value, this may support mm43's suggestion that: "the rudder aspect was such that the V/S was quite capable of "sailing" away..." Others may comment on wind and current. In case it's of interest: VS (fin) recovery position, relative to LKP (N02°58.8'/W030°35.4), is 29.9 nm (55.4 km) BRG 350°T Chris |
Chris, thanks for correcting my non-use of the silent K in the acronym.
The positions are from Table 1 of the Drift Analysis report. The only position observation in that table which is qualified is that for "Galley G2" sighting on June 6. (The qualification probably stems from the sighting and recovery coordinates being identical, even though the two events are four hours apart.) In re-looking at the Drift Analysis report, the only model of the eight used that came close to an impact near the LKP was the U.S. Navy's HYCOM model, and regarding its results: This [HYCOM] model gives a crash point near 3°15’N 30°30’W, and has been discarded from our analysis, on the basis that the velocity field is not realistic enough and the backtracked debris were scattered over 93 km (Figure 37). However the Ursulla sighting is backtracked not far from our 95% confidence area. The Ursulla object sighting was one of six objects for which trajectories were calculated backwards in time in each of the models. Interesting that the VS was not one of the six reference objects. |
It assumes all have accepted the discovered site as close to the LKP, but what are we considering "close?" Given the BEA's close to the vest attitude, the "close" could mean about anything. The bones thrown by BEA really do not provide enough information to formulate any true picture, only continued speculation. However, I expect a lot of our speculation to be right on point.
|
Aviation Week Summary
An update to a lot of what's being talked about on this forum
Aviation, Defense and Space News, Jobs, Conferences by AVIATION WEEK .... (Bloomberg) - Investigators seeking to explain why Air France flight 447 plunged into the night ocean two years ago will rely on gear pioneered by telecommunications and oil companies as well as a Hollywood director to unlock the mystery. The wreckage of the Airbus SAS A330 jet was discovered this month 3,900 meters (12,800 feet) deep in the Atlantic Ocean off the coast of Brazil after multiple searches. Few aircraft salvage missions have probed the same depth, where the sea is perfectly black, temperatures approach freezing and water pressure is equal to the weight of a car on a postage stamp. Diving deeper than the Titanic's final resting place, a robot tethered to a surface ship will sift through the aircraft debris in search of the two flight recorders bolted inside the tail of the fuselage. Their data promises the best chance yet to explain the crash, the deadliest in Air France's history. Complicating the mission is the presence of numerous bodies, some still strapped into their seats and preserved by the cold water and lack of oxygen or light. "At that depth, it is pitch black, and the difficulty is knowing where you are while keeping track of things," said Dave Gallo, director of special projects at the Woods Hole Oceanographic Research Institute in Falmouth, Massachusetts, whose robots helped locate and map the wreckage. "It's a question of operational skill." No Survivors The Airbus disappeared en route to Paris from Rio De Janeiro on June 1, 2009, leaving no survivors among the 228 aboard. While some fragments and bodies were recovered from the surface of the sea, most of the jet remained missing until this month. The data recorders are built to withstand submersion and extreme impact, though until retrieved there is no certainty the data they stored will be readable. The expedition will gather at the port in Dakar in Senegal tomorrow, before traversing the Atlantic on the Ile de Sein vessel to the location of the aircraft, about 435 nautical miles off the coast of Brazil. French phone-equipment maker Alcatel-Lucent SA is providing the 140-meter ship, which normally lays deep-sea cables. Aboard will be 70 people, including members of the French BEA air accident authority, investigators from the U.K. and Brazil, experts from Airbus and Air France, as well as one psychologist. Family members of the victims were not permitted aboard. Robot Submarines Underwater engineering company Phoenix International Holdings Inc. is sending one of its two "Remora" robotic submarines, or ROVs, equipped with high-resolution cameras and two manipulator arms. The basket on the ROV can recover as much as 200 kilograms (440 pounds) of debris in a single mission. "There are about six to eight ROVs in the world capable of descending as deep" as the Remora, said Tim Janaitis, business development manager at Phoenix, who spoke from Largo, Maryland. Typically, the robot's missions include work on deep-sea oil drilling, and a recent descent took the vehicle to the Titanic wreck in the northern Atlantic, Janaitis said. The search for the remains of the doomed ocean liner in the mid 1980s, and the 1997 blockbuster movie directed by James Cameron helped advance deep-sea technology, spawning high- resolution cameras and robots that can scour through wrecks. Nazi Battleship Following the success of the Titanic movie, which won 11 Academy Awards and cost about $200 million to make, Cameron embarked on an underwater expedition to Nazi battleship Bismarck, which sank in the Atlantic in 1941. "Stuff like that is enough at times to help keep research going," said Robert Jensen, chief executive officer of Kenyon International Emergency Services, a Houston-based company that helps airlines handle disasters. "Look at what they spent on the Cameron movies. He went down on several submersibles to look at ships, to recreate as realistically as possible what happened." The Remora robot can work as far down as 6,000 meters. To ensure steady operation, a team of nine Phoenix experts will operate the 900-kilogram sub from the ship using large video monitors to track its progress. Every movement of the vessel at the surface is translated to the Remora's umbilical cable with a delay, said Brennan Phillips, manager of ROV operations at the University of Rhode Island in the U.S. Delayed Reaction "If the ship moves, it takes half an hour for the vehicle to feel it," he said. "You need an extremely stable ship." Of the almost 100,000 photos taken of the wreck and surrounding area, BEA publicized several black-and-white images of the landing gear, an engine, a wing and parts of the fuselage. While the black boxes have not been spotted, the robot has located the part of the tail that normally houses the recorders. Investigators withheld images of bodies and made them available only to researchers involved in the mission. For some, the sight was too much to bear. "There were many bodies, and our people initially said they would not like to participate in any such recovery operation," said Peter Herzig, director of the Leibnitz Institute of Marine Sciences in Kiel, northern Germany, whose Remus 6000 robot sub was one of three that located the wreck. Team members later changed their minds, though in the end, Herzig's group wasn't asked to participate, he said. Should the recorders be found, they will be pried from the wreck, lifted aboard the Ile de Sein and immediately placed under seal, before being transported by a French Navy vessel to a French port. From there, they will be sent by air to the BEA under the responsibility of a judicial police officer. Recovering Bodies Recovering the victims is a more complex and contentious task. Only 51 bodies, including the pilot, were recovered from the ocean surface in the weeks after the crash. Nelson Marinho, who leads a group of victims' relatives, said not all families want to see corpses brought up, though they recognize the obligation to present forensic evidence for a criminal probe. A French prosecutor is pursuing allegations of manslaughter against both Airbus and Air France, and autopsies may help answer questions such as whether passengers were still alive when the plane sank. BEA said all decisions concerning human remains will be made by France's Justice Department. "The worst feeling, for us, is the risk of even more damage to these corpses," Marinho said. "French officials want to transport them to France, but we want to bring them directly to Brazil." Among the victims were 58 passengers from Brazil, 61 from France, 26 from Germany, and other nationalities including travelers from China and South Korea. TWA Crash Past aircraft salvage missions have managed to recover the bodies of victims. The U.S. National Transportation Safety Board brought up all the bodies from TWA flight 800, which crashed off Long Island in 1996, and EgyptAir 990, which went down 60 miles from Nantucket in 1999, former director Jim Hall said. "I think as human beings, it's the humane practice, and it would be a disservice to family members by the airline and regulators not to recover them," he said. The greatest technical challenge will remain operating at an extreme depth. Only one past air crash has forced salvage teams to dive deeper. The wreckage and black boxes of a South African Airways Boeing 747 that disappeared near Mauritius in 1987 were located 14 months later under 14,000 feet of water. "It's only relatively recent that we even have the technology to consider these kind of recoveries," said Paul Hayes, director of safety at London-based aviation consultant Ascend Worldwide Ltd. "And it sounds simplistic, but I think we tend to forget how vast the oceans are." |
Of the almost 100,000 photos taken of the wreck and surrounding area, BEA publicized several black-and-white images of the landing gear, an engine, a wing and parts of the fuselage. While the black boxes have not been spotted, the robot has located the part of the tail that normally houses the recorders. Investigators withheld images of bodies and made them available only to researchers involved in the mission. For some, the sight was too much to bear. |
wes wall and SaturnV (have you seen the Haynes Manual in the UK?),
Don't have to tell you that this topic has been discussed at length on this or the old thread. With that sense of déjà-vu, I've been trawling through the pages from this time last year, so far without success. (No doubt the antipodal mm43 will remind us later where to find it.) SaturnV, Regret I've no expertise in this area. Is "HYCOM" the same as the "NCOM" referred to in BEA Interim Report 2, page 79? Looking at BEA Interims 1 & 2, I've noticed a discrepancy on the recovery position of the fin. This makes a complete nonsense of the 29-hour "voyage" (for want of a better expression) in my post above, in terms of both track and distance. Can you confirm the source of the recovery position you quoted: "VS recovered June 7 @ 18h35 @ 3.47N 30.68W" ? Unless I've missed it, neither report specifies the Lat/Long, but the map in Interim 1 (enlarged slightly in the Appendix, page 107) has the June7-"recovery" diamond position-symbol at about: N03° 36'/W030° 37', i.e., in the language of your quote, 3.60N 30.62W. That looks almost identical to the "sighted" June 6 position you quoted. Can you shed any light? [EDITED ADDITION]: See my subsequent post (#3743 next page). wes wall, (quote): It assumes all have accepted the discovered site as close to the LKP, but what are we considering "close?" Given the BEA's close to the vest attitude, the "close" could mean about anything. You say that if you like; I couldn't possibly comment... Chris |
henra
Without VS/Rudder, both JAL 747 and Sioux City DC10 'landed' flat. Pilots were active and had some control, but we haven't determined that P1P2 on the deck of 447 didn't have same. So loss of directional control structure does not mean nose first dive necessarily?? 587 had lost all controls due to loss of both engine structures. 587 also had presumably alive alert pilots after VS/R loss. rgds. Chris Scott I still await mm43's response. He mentioned the winds at surface LKP as 000@25-30, does not this conflict with a Northerly drift of the VS. Of course that doesn't take into account the actual crash site. Razoray I am always hopeful of strong and important changes to the industry to emanate from the finality of such a heartbreaking tragedy. These changes are entirely dependent on BEA and their report, for they have the tools and the evidence to make this fateful flight an eternal memory of people who perished for good of others. My hope is that a new level of disclosure and openness will evolve in the results of this. Flying is uncommonly safe, and we are all human, so things go wrong sometimes. It must be made safer. |
Reading between the lines of the Bloomberg articles, it would seem that Alucia and two Remus subs will rejoin the effort. I would think Woods Hole has produced a detailed mosaic map of everything, given the quantity of pictures. The question becomes, how intact is the tail, and how much cutting will be needed to access where the recorders presumably are?
|
Chris Scott,
My pdf version on the BEA Second Interim report only goes to p. 72, so I can't speak to the reference you cite. The latitude and longitude coordinates for the sightings and recoveries are from Table 1 of the "BUREAU D’ENQUETES ET D’ANALYSES POUR LA SECURITE DE L’AVIATION CIVILE Scientific Report from the Drift Group" Published on June 30 2010 This is Table 1 in non-tabular format Ursulla sighting U June 5 2009 at 16h10 3.63N 30.45W Brazilian sighting 1 S1 June 5 2009 at 21h02 3.56N 30.44W 3m part sighting 2 S2 June 6 2009 at 10h59 3.47N 30.47W Galley G213 (sighted)G2 June 6 2009 at 11h06 3.47N 30.66W First two bodies BB June 6 2009 at 11h55 3.57N 30.46W Galley G2 (recover.) June 6 2009 at 15h00 3.47N 30.66W Case June 6 2009 at 16h10 3.46N 30.63W Body E1 (sighted) E1 June 7 2009 at 9h11 3.65N 30.51W Vertical fin(sighted) VTP June 7 2009 at 13h38 3.61N 30.62W Body 2Z (recover.) June 7 2009 at 16h39 3.70N 30.50W Body 3Z (recover.) 3Z June 7 2009 at 17h17 3.73N 30.48W Body 6Z (recover.) June 7 2009 at 17h29 3.74N 30.48W Body 4Z (recover.) June 7 2009 at 17h41 3.75N 30.47W Vertical fin(recover.) June 7 2009 at 18h35 3.47N 30.68W Body 5Z (recover.) June 7 2009 at 18h55 3.73N 30.47W Body 7Z (recover.) June 7 2009 at 20h35 3.75N 30.47W Body 8Z (recover.) June 8 2009 at 16h58 4.04N 30.46W Body 9Z (recover.) June 8 2009 at 17h25 4.03N 30.45W Body 10Z (recover.) June 8 2009 at 17h50 4.06N 30.44W Body (recover.) June 8 2009 at 18h34 4.06N 30.43W Body (recover.) June 8 2009 at 19h25 4.08N 30.43W Body (recover.) June 8 2009 at 19h56 4.09N 30.43W Body 11Z (recover.) June 9 2009 at 9h45 4.25N 30.44W Body 12Z (recover.) June 9 2009 at 10h16 4.25N 30.43W Body 13Z (recover.) June 9 2009 at 11h02 4.25N 30.41W Body 14Z (recover.) June 9 2009 at 12h29 4.27N 30.42W Body 15Z (recover.) June 9 2009 at 12h56 4.27N 30.43W Body 16Z (recover.) June 9 2009 at 13h29 4.31N 30.45W Body 17Z (recover.) June 9 2009 at 14h21 4.31N 30.51W Body 18Z (recover.) June 9 2009 at 15h45 4.35N 30.52W Body 19Z (recover.) June 9 2009 at 15h45 4.35N 30.52W Body 20Z (recover.) June 9 2009 at 16h24 4.41N 30.52 13 Not fully confirmed Table 2 Mean crash positions and estimated standard deviations for the seven models selected. Lat Long Standard deviation Model 3.579 -30.869 48 ZOOM2 3.673 -30.675 48 ZOOM2+ Stokes 3.364 -30.911 35 FVCOM 3.372 -30.856 35 FVCOMW 3.554 -30.756 20 OI50 3.590 -30.537 20 OI85 3.393 -30.983 40 PSY2AVG data fitted This is the detail on HYCOM. This global 1/12° ocean forecasting system is run at NRL Stennis Space Center. It uses 32 vertical hybrid layers. Surface mixing is parameterized with Large et al.’s (1997) K Profile Parameterization (KPP) surface ocean boundary layer model. The surface is forced by 3-hourly wind stress, wind speed, heat flux (using bulk formula) and precipitation from the Navy Operational Global Atmospheric Prediction System (NOGAPS). Runoff from 986 rivers is included as a virtual salinity flux with no mass exchange. The system assimilates (i) SSH from Envisat, Jason-1 and Jason-2 (ii) SST from all available satellite and in situ sources, (iii) all available in situ temperature and salinity profiles (e.g., Argo, CTDs, moor- ings), and (iv) Special Sensor Microwave/ Imager (SSMI) sea ice concentration. Assimilation is performed using the three-dimensional MultiVariate Optimum Interpolation (MVOI) Navy Coupled Ocean Data Assimilation (NCODA) system (Cummings, 2005). In this scheme, corrections to the model state are obtained by linear combinations of model-observation differences. The MVOI analysis is carried out on 42 z-levels extending from the surface down to 2500 m. The model forecast is interpolated to z-levels before the analysis and the analyzed increments are added to the forecast and interpolated back to the model's hybrid vertical coordinate. |
bearfoil, quote:
"Without VS/Rudder, both JAL 747 and Sioux City DC10 'landed' flat." No Sir, the UAL DC10 landed at Sioux City with its fin intact, and (unpowered) rudder in place. Those guys did an absolutely brilliant job, but am confident they would be the first to say that they would never have made it without a fin. The JAL 747 guys also did a brilliant job, but never had a chance to attempt a landing with their finless aeroplane. |
I stand corrected on UAL, I recall that the disintegrating Fan severed hydraulics in the Fin, and Directional control was lost due to unpowered Rudder. This is somewhat counter to my belief that the VS is critical, the Rudder, not so. As JAL shows, I think they remained relatively in control, but meandered in heading until they impacted the mountain. My point is that a fairly level arrival is possible w/o the Fin. Again, we don't know that 447's pilots were not alert and had no management of Pitch. The fact that 447 was laterally rotating supports the loss of the Vertical Stabilizer, anent JD-EE's maple leaf (acer helix). This is not to say that 447 lost her fin at altitude, she may have lost it much lower, its loss perhaps initiating 447's lateral rotation.
587 does not apply here, imo. |
Thanks SaturnV,
For confirming the VS (fin) positions you originally quoted. Therefore, tentatively, the 29-hour "voyage" of the VS-rudder assembly still stands, subject to the accuracy of the "sighted" position of June 6. Guess the map that appears twice in BEA Interim Report 1 must be wrong. I'm wondering what effect the close-proximity of the north-migrating ITCZ (front inter-tropique) may have had on the accuracy of surface-wind estimations. To be simplistic: (a) with the ITCZ just south of the crash zone, would the surface-wind have been in the north-east? (b) if the ITCZ had already passed through (say at 4° N), might the crash-site surface-wind have been between south-east and south-west? (c) if overhead the crash zone, would it have been light and variable ("Doldrums")? Perhaps our nautical/meteorological colleagues may comment? Thanks also for including all the other stuff: will try to assimilate. |
The question becomes, how intact is the tail, and how much cutting will be needed to access where the recorders presumably are? |
This may be lunacy, but is there a way to re-invigorate the pinger?? Is there a chip, summat for alternate method of location when in the vicinity? Passive?? RFID? 'Course the boxes may already be on some of the 100k images. Hopeful.
|
Wow, 100.000 images.
That is what I would call a detailed scan. Regarding finding the black bokes Taking into consideration that these are relatively heavy compact boxes of simple shape, it is likely they won't drift to far even if broken free from the tail. Had they broken lose upon impact I would expect them rather close to other heavy dense items (e.g. the engines or the landing gear). Would btw be interesting to know how far the engines were found from the front landing gear. So even in that case I'm rather confident they will find them. May take a little while but now the area to be searched is down to a reasonable size. And due to the above mentioned reason I do not expect the FDR /CVR to be the part of 'outliers'. They should be either at the beginning of the trail close to the center line of the trail or inside the tail. Also hopeful |
Originally Posted by bearfoil
(Post 6404564)
henra
Without VS/Rudder, both JAL 747 and Sioux City DC10 'landed' flat. As has already been pointed out the DC-10 did not lose its VS. The JAL 747 did indeed lose most of its VS. (There is a crude image existing which shows a small remaining fragment of the VS on the tail). And indeed the pilots miraculously managed to keep some control of the plane (Maybe having 4 engines with long moment arms helped a little). However from what I understood they did not 'pancake', i.e. they never really stalled or spinned the plane they just lost directional control in the sense that they could not really control where it was going. They also lost pitch control due to loss of the hydraulics. Upon impact it still had significant forward speed when they hit the mountain ridges Had they really stalled it I'm sure it would have gone into a spiral dive similar to AA587 and gone in in a forward high speed impact. In that case surely not a single person would have survived |
Chris Scott,
On the winds, there are four pages with numerous graphs, devoted to the winds in the Drift Analysis report. Here's an excerpt. Several wind products are available for our study area and period. All come from numerical weather prediction (NWP) models assimilating a large amount of meteorological data (measured in-situ or remotely). Three global (i.e. world covering) wind fields have been used: NCEP (named after the National Centers for Environmental Prediction), ECMWF (named after the European Center for Mediumrange Weather forecast) and an experimental version of ARPEGE from Météo-France. Actually, both the operational products and their reanalysis (NRA-2, ERA Interim) were used. A reanalysis is a new run of the model but with assimilation of more and fully validated past data (thus it is not a forecast but a “hindcast”). Time resolution is four times daily (0h, 6h, 12h and 18h) and the spatial grid is a 0.5° regular one in longitude and latitude over the ACARS zone. However, the ARPEGE version has a finer 0.18° mesh size and 1 hourly wind outputs (see C. Payan report for details). Figure 13 shows the ECMWF winds (at 10 m above the sea surface) and cumulonimbus clusters on June 1 every 6h. Southward winds are prevailing north of LKP, and there is a strong convective activity (with heavy rains) over the zone except in the Northwest. During the following days winds slackened and veered to easterly trades, while the convective activity decreased drastically. |
BBC Report on AF 447
BBC do another brief analysis of wreckage location and BB recovery possibilities. BBC News - Air France crash: The long hunt for answers
Not much new me thinks - they might have trawled (pun intended:hmm:) much of it here anyhow! Sorry if this link has been posted before, a quick search didn't find it. Mods please feel fee to delete if this has been covered already. |
When things float ...
Originally posted by bearfoil ... The V/S was semi submerged when spotted, its colors probably difficult to discern. The structure gave me the impression of never being 'proud' of the surface, and I assumed it acted as its own sea anchor from loss to discovery. BEA stated that the Rudder was flapping, and had no resistance to pressure in its axis of sweep. I do not think it "sailed" at all. The BEA's description of the rudder was for the "in air" condition, but the "in water" condition was modified by the application of Archimedes' principle. As I have stated previously the V/S found itself in the water floating portside down, and flooding in the lower sections of the fin caused the line through the rudder hinge joints to sink deeper, especially at its base. This sinking condition was overcome by the bouyancy of the rudder, and the rudder moved to its maximum physical position of 35° to starboard. The overall effect was that the trailing edge of the rudder was level with the sea surface and around 2 meters above it. This condition is clearly evident in the low resolution screenshot taken from the BBC2 documentary where the fortuitous sun angle provides suitable shadow, and is reproduced below. http://i52.tinypic.com/292o743.jpg Another couple of screenshots from the BBC2 documentary reproduced below, may help with visualizing the manner in which the V/S was floating. http://i55.tinypic.com/145jde.jpg http://i54.tinypic.com/34h8fmw.jpg So, mon ami, the fin/rudder combination floated, had a breached buoyancy condition which provided a form of keel, and the rudder provided the surface area for the wind to interact with. Apologies for the delayed posting. A family members house moving venture delayed proceedings. |
I heard from someone close to inquiry that BEA have located the wrekage that should contain the recorders, and have also located the main passenger compartments, but main fusleage is broken into a few pieces. Pictures of this have been witheld for obvious reasons. So the recorders should be in Paris soon.
|
Hi,
The Remora robot can work as far down as 6,000 meters. To ensure steady operation, a team of nine Phoenix experts will operate the 900-kilogram sub from the ship using large video monitors to track its progress. Every movement of the vessel at the surface is translated to the Remora's umbilical cable with a delay, said Brennan Phillips, manager of ROV operations at the University of Rhode Island in the U.S. Delayed Reaction "If the ship moves, it takes half an hour for the vehicle to feel it," he said. "You need an extremely stable ship." |
Originally Posted by bearfoil @ 21st Apr 2011 09:40
As JAL shows, I think they remained relatively in control, but meandered in heading until they impacted the mountain. My point is that a fairly level arrival is possible w/o the Fin.
The only example we have to go by which speaks to loss of the VS before impact is the AA587 accident, which crashed immediately. The separation of the engines from the airframe was due to high lateral loads, due to the loss of the vertical stabilizer. |
MurphyWasRight, "There may be confusion here between time stamps,synchronous sampling and lower than nyquist sample rate artifacts," is right on the mark. Our good friend Nyquist is what syseng68k was forgetting about. The tick marks for left and right elevator are at different
times. You MAY be able to put the two streams together and derive what the elevator was really doing at the time. There will be some lag between their actuators. So some difference may be visible. Calibration tolerances may lead to further differences. In this case if you simply draw the line through both sets of points you get a fairly decent picture of what the elevator as a whole was doing. And it's pretty clean about it. |
| All times are GMT. The time now is 05:41. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.